Accessible Downhole Power Assembly

ABSTRACT

In one aspect of the present invention, a downhole power assembly has a downhole drill string component having a center mandrel with a through-bore adapted to accommodate a flow of drilling fluid. The component has an independent tubular battery cage disposed around the center mandrel. At least one battery is disposed in at least one bay formed in the tubular battery cage and a tubular sleeve is adapted to slide over and cover the tubular battery cage.

BACKGROUND OF THE INVENTION

The present invention relates to downhole drilling, and moreparticularly, to systems and methods for installing and accessingbatteries in a downhole tool string.

U.S. Pat. No. 6,899,178 to Tubel, which is herein incorporated byreference for all that it contains discloses tools for deploymentdownhole in a wellbore for aiding in the production of hydrocarbons. Inan exemplary embodiment, the tools comprise a tool body; an electricallypowered device disposed proximate the tool body; a removable powersource for providing power to the device disposed in the tool body, thepower source connected to or mounted into or about the tool body, thepower source further being fixed or replaceable downhole; and a wirelesscommunications device operatively connected to the electrically powereddevice.

U.S. Pat. No. 4,884,071 to Howard, which is herein incorporated byreference for all that it contains, discloses an improved wellbore toolfor coupling to a drill string at a threaded junction and adapted foruse in a wellbore during drilling. A sensor is disposed in the wellboretool for sensing a condition and producing a data signal correspondingto the condition. A self-contained power supply is disposed in thewellbore tool and coupled to the sensor for providing power to thesensor as required. The Hall Effect coupling transmitter means iscarried by the sensor and for transmitting data from the Hall Effectcoupling receiver carried by the drill string and disposed across thethreaded junction from the wellbore tool, wherein data is transmittedacross the threaded junction without requiring an electrical connectionat the threaded junction.

U.S. Pat. No. 6,442,105 to Tubel, which is herein incorporated byreference for all it contains, discloses an acoustic transmission systemwherein acoustic communication is transmitted over an acoustic mediumcomprising production tubing, well casing or over continuous tubing in awell (e.g., coil tubing, chemical injection tubing or dewateringstring). More specifically, the acoustic medium has an acoustic toolassociated therewith, which is permanently located downhole with thesensors and electromechanical devices typically employed in a well, andan acoustic tool associated therewith uphole. The downhole sensors areconnected to the downhole acoustic tool for acoustic communication. Theacoustic tool includes a piezoelectric ceramic transducer (i.e., a stackof piezoelectric elements) or an accelerometer for transmitting orreceiving acoustic signals transmitting through the medium.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a downhole power assembly has adownhole drill string component having a center mandrel with athrough-bore adapted to accommodate a flow of drilling fluid. Thecomponent has an independent tubular battery cage disposed around thecenter mandrel. At least one battery is disposed in at least one bayformed in the tubular battery cage and a tubular sleeve is adapted toslide over and cover the tubular battery cage.

A sleeve slide guide is disposed around the center mandrel adjacent tothe tubular battery cage and comprises a length at least equal to alength of the tubular battery cage. The sleeve slide guide may have afirst end with an outer diameter smaller than an inner diameter of thetubular sleeve and a second end with an outer diameter greater than theinner diameter of the tubular sleeve. The first end of the sleeve slideguide may be adapted to abut against an end of the tubular battery cage.The tubular sleeve may be adapted to slide off of the tubular batterycage onto the sleeve slide guide. The tubular sleeve may have a lockingcollar adapted to be bolted to the tubular battery cage restricting themovement of the tubular sleeve.

The downhole power assembly may have an electrical contact disposed at afirst end of the tubular battery cage adapted to transfer electricalpower from the downhole power assembly to an electronics assembly. Theelectronics assembly may be disposed around the center mandrel of thedownhole drill string component. The electronics assembly may bedisposed on another downhole drill string component. The electronicsassembly may comprise a geophone, a hydrophone, or combinations thereof.

At least one mechanical retainer may be disposed in the at least one bayand is adapted to mechanically retain the at least one battery in the atleast one bay. The mechanical retainer may have an extending pin adaptedto extend from a body of the mechanical retainer into the at least onebay. The extending pin may be spring actuated, actuated by a biaseddriving element, piston actuated, or combinations thereof.

The downhole power assembly may have at least one electrical connectoradapted to provide an electrical connection between the at least onebattery and a power network of a downhole tool component independent ofthe mechanical retention of the at least one battery in the at least onebay. The at least one electrical connector may have an expandableelement disposed in a box adapted to extend a plunger contact through ahole formed in a lid of the box. The expandable element may be a spring,a wave spring, a coil spring, compressible foam, rubber, gas, orcombinations thereof. The expandable element may be adapted to extend asecond plunger contact through a hole formed in a bottom of the box.

The tubular battery cage may have five bays connected electrically inparallel to a positive junction and a negative junction. An electricalgenerator may be disposed in another downhole tool string component andmay be adapted to send electrical power across at least one annularmagnetic coupler to the at least one battery. The downhole powerassembly may be adapted to send power across the at least one annularmagnetic coupler to another downhole drill string component.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of an embodiment of a drill stringsuspended in a bore hole.

FIG. 2 is a perspective diagram of an embodiment of a downhole drillstring component.

FIG. 3 a is a prospective diagram of an embodiment of an independenttubular battery cage

FIG. 3 b is a prospective diagram of another embodiment of anindependent tubular battery cage.

FIG. 3 c is a prospective diagram of another embodiment of anindependent tubular battery cage.

FIG. 4 is a cross-sectional diagram of an embodiment of an independenttubular battery cage disposed around a center mandrel.

FIG. 5 a is a cross-sectional diagram of an embodiment of a mechanicalretainer.

FIG. 5 b is a cross-sectional diagram of another embodiment of amechanical retainer.

FIG. 6 is a cross-sectional diagram of an embodiment of an electricalconnector.

FIG. 7 is a perspective diagram of an embodiment of an independenttubular battery cage disposed around a center mandrel.

FIG. 8 is a perspective diagram of an embodiment of a first end of thetubular battery cage.

FIG. 9 is a cross-sectional diagram of another embodiment of anelectrical connector.

FIG. 10 is a cross-sectional diagram of an embodiment of a downholegenerator in communication with a downhole power assembly.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a perspective diagram of an embodiment of a downhole drillstring 100 suspended by a derrick 108 in a bore hole 102. A drillingassembly 103 is located at the bottom of the bore hole 102 and comprisesa drill bit 104. As the drill bit 104 rotates downhole the downholedrill string 100 advances farther into the earth. The downhole drillstring 100 may penetrate soft or hard subterranean formations 105. Thedrilling assembly 103 and/or downhole components may comprise dataacquisition devices which may gather data. The data may be sent to thesurface via a transmission system to a data swivel 106. The data swivel106 may send the data to the surface equipment. Farther, the surfaceequipment may send data and/or power to downhole tools, the drill bit104 and/or the drilling assembly 103. U.S. Pat. No. 6,670,880 which isherein incorporated by reference for all that it contains, discloses atelemetry system that may be compatible with the present invention;however, other forms of telemetry may also be compatible such as systemsthat include mud pulse systems, electromagnetic waves, radio waves,wired pipe, and/or short hop.

Referring now to FIGS. 2 through 4, the downhole drill string 100comprises a downhole power assembly 204. The downhole power assembly 204comprises a downhole drill string component 201 with a center mandrel205 comprising a through-bore 206 adapted to accommodate a flow ofdrilling fluid. The center mandrel 205 may comprise a first end 203 anda second end 202 adapted to connect the downhole drill string component201 to the downhole drill string 100. The downhole drill stringcomponent 201 comprises an independent tubular battery cage 301 disposedaround the center mandrel 205. At least one bay 303 is formed in theindependent tubular battery cage 301 and at least one battery 302 isdisposed in the at least one bay 303. The downhole power assembly 204also comprises a tubular sleeve 304 adapted to slide over and cover thetubular battery cage 301. A sleeve slide guide 305 may be formed aroundthe center mandrel 205 adjacent to the tubular battery cage 301 whichprovides a surface upon which the sleeve may slide. In some embodiments,the sleeve guide comprises a similar diameter and length as the tubularbattery cage 301. The sleeve slide guide 305 may comprise a first end207 with an outer diameter 208 smaller than an inner diameter of thetubular sleeve 304 and a second end 209 with an outer diameter 210greater than the inner diameter of the tubular sleeve 304. The first end207 of the sleeve slide guide 305 may be adapted to abut against an endof the tubular battery cage 301. It is expected that the tubular sleeve304 will be adapted to slide off of the tubular battery cage 301 ontothe sleeve slide guide 305 allowing access to the at least one battery302 while the downhole drill string component 201 is connected to thedownhole drill string 100. The tubular sleeve 304 may comprise a lockingcollar 211 adapted to be bolted to the tubular battery cage 301 therebypreventing the tubular sleeve 304 from moving and exposing the tubularbattery cage 301. O-rings 307 may be disposed on the tubular batterycage 301 and may provide a water-tight seal between the tubular batterycage 301 and the tubular sleeve 304 thereby protecting the tubularbattery cage 301 and the at least one battery 302 from fluids disposedin the bore hole 102. In U.S. Pat. No. 6,442,105 to Tubel, which isherein incorporated by reference for all that it contains, discloses anacoustic tool comprising a mandrel with a sleeve adapted to covercavities machined into the mandrel to accommodate components of theacoustic tool including a battery pack assembly. It is believed thatmachining cavities into a mandrel negatively impacts the structuralintegrity of the mandrel. It is believed that the present inventionprovides a mode by which batteries 302 may be stored on the mandrel 205without negatively impacting the structural integrity of the mandrel205.

The downhole power assembly 204 may be in communication with and provideelectrical power to an electronics assembly 213. The electronicsassembly 213 may be disposed around the center mandrel 205 and adjacentto the tubular battery cage 301. The electronics assembly 213 maycomprise but geophones 214, hydrophones 215, or combinations thereof.The electronics assembly 213 may also comprise accelerometers,inclinometers, pressure transducers, magnetometers, gyroscopes,temperature sensors, gamma ray sensors, neutron sensors, seismicsensors, sonic sensors, mud logging devices, resistivity sensors,induction sensors, nuclear sensors, imaging devices, GPS devices,Hall-effect sensors, permeability sensors, porosity sensors, vibrationsensors, electrical potential sensors, geophones, a downhole hammer, amud pulser, a CPU or combinations thereof The tubular sleeve 304 maycomprise a hydrophone cover 216 adapted to protect the hydrophones 215.Left threaded nuts 217 may be placed on the center mandrel 205 torestrain the movement of the electronics assembly 213, the tubularbattery cage 301, and the sleeve slide guide 305 along a length of thecenter mandrel 205.

The at least one bay 303 may be adapted to accommodate a battery pack306 comprising at least two batteries 302. The battery pack 306 maycomprise two end caps 504 and to two length straps 505 connectedtogether to enclose the at least two batteries 302. At least oneelectrical connector 401 may be incorporated into the end caps 504 ofthe battery pack 306 and is adapted to provide an electrical connectionbetween the batteries 302 and an electrical lead 402 disposed in the atleast one bay 303. The battery pack 306 may comprise an adjustablepacking bumper 406 adapted to pack the batteries 302 in the battery pack306 tightly against each other. The adjustable packing bumper 406 maycomprise a bumper pad 408 and supporting lugs 407. As the battery pack306 is assembled, the adjustable packing bumper 406 may be adjusted soas to fit different sized batteries 302 into the battery pack 306.

Referring now to FIG. 5, at least one mechanical retainer 500 may bedisposed in the at least one bay 303 and may be adapted to mechanicallyretain the at least one battery 302 in the at least one bay 303. The atleast one mechanical retainer 500 may also be adapted to retain thebattery pack 306 in the at least one bay 303. A bolt 509 may be used tomount the at least one mechanical retainer 500 to the tubular batterycage 301 in the at least one bay 303. The mechanical retainer 500 maycomprise an extending pin 502 adapted to extend from a body 501 of themechanical retainer 500 into the at least one bay 303. The extending pin502 may be spring actuated, actuated by a biased driving element 503,piston actuated, or combinations thereof. In FIGS. 5 a and 5 b theextending pin 502 is actuated by a biased driving element 503 disposedin a recess 508 formed in the body 501 of the mechanical retainer 500.The biased driving element 503 disclosed in FIGS. 5 a and 5 b may bedriven into the recess 508 and against the extending pin 502 by a hexkey 308 or a screw driver. As the biased driving element 503 is drivenagainst the extending pin 502, the extending pin 503 extends from thebody 501 of the mechanical retainer 500 into the at least one bay 303and applies pressure against the at least one battery 302 or one of theend caps 504 of the battery pack 306. It is believed that the pressureapplied against the at least one battery 302 or the battery pack 306 bythe extending pin 502 will mechanically retain the at least one battery302 or the battery pack within the at least one bay 303.

FIG. 6 discloses an embodiment of the at least one electrical connector401 incorporated into an end cap 504 of the battery pack 306. The atleast one electrical connector 401 may comprise an expandable element601 disposed in a box 603 adapted to extend a plunger contact 602through a hole 605 formed in a lid 604 of the box 603. The expandableelement may be a spring, a wave spring, a coil spring, compressiblefoam, rubber, gas, or combinations thereof. The embodiment of theexpandable element disclosed in FIG. 6 is a wave spring. As the plungercontact 602 extends through the hole 605 formed in the lid of the box603, the plunger contact 602 is expected to contact the electrical lead402 of the at least one bay 303. The at least one electrical connector401 may comprise a coil spring 610 adapted to extend through a hole 607formed in a bottom 606 of the box 603 and contact the plunger contact602 and a terminal of the battery 302. It is believed that the at leastone electrical connector 401 may be adapted to provide an electricalconnection between the at least one battery 302 and the electronicsassembly 213 independent of the mechanical retention of the at least onebattery 302 in the at least one bay 303. It is believed that electricalcurrent 650 will travel from the battery 302 through the coil spring 610into the plunger contact 602 and from the plunger contact 602 into theelectrical lead 402 of the at least one bay 303. The electrical lead 402may extend through the body 501 of the mechanical retainer 500 to ajunction wire 611 adapted to carry the electrical current 650 outside ofthe at least one bay 303. A channel 613 may be formed in the tubularbattery cage 301 to accommodate the junction wire 611. An insulationelement 612 may be disposed around the electrical lead 402 and may beadapted to electrically isolate the electrical lead 402 from the body501 of the mechanical retainer 500.

Referring now to FIGS. 7 through 8, the junction wire 611 electricallyconnects the at least one bay 303 to a positive junction 403 and anegative junction 705. The tubular battery cage 301 may comprise fivebays 303 connected electrically in parallel to the positive junction 403and the negative junction 705. The junctions may connect to anelectrical contact 701 through wires 706, 405. The electrical contactmay be in electrical communication with electronics 213 elsewhere in thedownhole component. The electrical contact 701 may be disposed at afirst end 702 of the tubular battery cage 301. The electrical contactmay be mounted on a circular circuit board 703 disposed at a first end702 of the tubular battery cage 301.

FIG. 9 discloses an embodiment wherein the electrical connector 401 maycomprise a second plunger contact 901. The expandable element 601 may beadapted to extend the second plunger contact 901 through the hole 607formed in the bottom 606 of the box 603.

Referring now to FIG. 10, an electrical generator 1001 may be disposedin another downhole tool string component 1000 and may be adapted tosend electrical power across at least one inductive coupler 1004 to theat least one battery 302 thereby recharging the at least one battery302. An embodiment of an inductive coupler 1004 that may be compatiblewith the present invention is disclosed in the patent application Ser.No. 11/860,795 to Hall, which is herein incorporated by reference forall it contains. The electronics assembly 213 may also be disposed onthe other downhole drill string component 1000. In the embodimentdisclosed in FIG. 10, the electronics assembly 213 comprises a CPU 1003adapted to regulate the flow of electrical power across the inductivecoupler 1004. The electrical generator 1001 may be powered by a downholeturbine 1002 actuated by the flow of drilling fluid through the downholedrill string 100. The downhole power assembly 204 may be adapted to sendpower across the at least one inductive coupler 1004 to the otherdownhole drill string component 1000.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications apart from those shown or suggested herein, may bemade within the scope and spirit of the present invention.

1. A downhole power assembly, comprising: a downhole drill stringcomponent comprising a center mandrel with a through-bore adapted toaccommodate a flow of drilling fluid; the component comprising anindependent tubular battery cage disposed around the center mandrel; atleast one battery disposed in at least one bay formed in the tubularbattery cage; and a tubular sleeve adapted to slide over and cover thetubular battery cage.
 2. The assembly of claim 1, wherein a sleeve slideguide is disposed around the center mandrel adjacent to the tubularbattery cage and comprises a length at least equal to a length of thetubular battery cage.
 3. The assembly of claim 2, wherein the sleeveslide guide comprises a first end with an outer diameter smaller than aninner diameter of the tubular sleeve and a second end with an outerdiameter greater than the inner diameter of the tubular sleeve.
 4. Theassembly of claim 3, wherein the first end of the sleeve slide guide isadapted to abut against an end of the tubular battery cage.
 5. Theassembly of claim 2, wherein the tubular sleeve is adapted to slide offof the tubular battery cage onto the sleeve slide guide.
 6. The assemblyof claim 1, wherein the tubular sleeve comprises a locking collaradapted to be bolted to the tubular battery cage restricting themovement of the tubular sleeve.
 7. The assembly of claim 1, wherein thedownhole power assembly comprises an electrical contact disposed at afirst end of the tubular battery cage adapted to transfer electricalpower from the downhole power assembly to an electronics assembly. 8.The assembly of claim 7, wherein the electronics assembly is disposedaround the center mandrel of the downhole drill string component.
 9. Theassembly of claim 7, wherein the electronics assembly is disposed onanother downhole drill string component.
 10. The assembly of claim 9,wherein the electronics assembly comprises a geophone, a hydrophone, orcombinations thereof.
 11. The assembly of claim 1, wherein at least onemechanical retainer is disposed in the at least one bay and is adaptedto mechanically retain the at least one battery in the at least one bay.12. The assembly of claim 11, wherein the mechanical retainer comprisesan extending pin adapted to extend from a body of the mechanicalretainer into the at least one bay.
 13. The assembly of claim 12,wherein the extending pin is spring actuated, actuated by a biaseddriving element, piston actuated, or combinations thereof.
 14. Theassembly of claim 11, wherein the downhole power assembly comprises atleast one electrical connector adapted to provide an electricalconnection between the at least one battery and a power network of adownhole tool component independent of the mechanical retention of theat least one battery in the at least one bay.
 15. The assembly of claim14, wherein the at least one electrical connector comprises anexpandable element disposed in a box adapted to extend a plunger contactthrough a hole formed in a lid of the box.
 16. The assembly of claim 15,wherein the expandable element is a spring, a wave spring, a coilspring, compressible foam, rubber, gas, or combinations thereof.
 17. Theassembly of claim 15, wherein the expandable element is adapted toextend a second plunger contact through a hole formed in a bottom of thebox.
 18. The assembly of claim 1, wherein the tubular battery cagecomprises five bays connected electrically in parallel to a positivejunction and a negative junction.
 19. The assembly of claim 1, whereinan electrical generator disposed in another downhole tool stringcomponent is adapted to send electrical power across at least oneinductive coupler to the at least one battery.
 20. The assembly of claim19, wherein the downhole power assembly is adapted to send power acrossthe at least one inductive coupler to another downhole drill stringcomponent.